{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T12:35:58Z","timestamp":1793104558189,"version":"4.5.0"},"reference-count":23,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"9","license":[{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Clozapine therapeutic drug monitoring (TDM) supports individualized dosing in treatment-resistant schizophrenia.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Aim<\/jats:title>\n                    <jats:p>This study evaluated the time trend of TDM reporting in routine practice.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A retrospective audit of 100 consecutive clozapine TDM reports over 4 years was performed. Service utilization was assessed. Associations between daily dose, trough concentration, concentration\u2013dose (C\/D) ratio, therapeutic impressions (low, matching the dose, high, very high clozapine concentrations), and clinical advice accordingly were analyzed statistically.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The mean turnaround time was 20.9 \u00b1 12 days, with a stable quarterly demand (~6 requests\/quarter) for clozapine TDM. Dose correlated significantly with trough concentration (\u03c1 = 0.453,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.001). Forty-seven percent of concentrations were subtherapeutic. C\/D ratio differed significantly between therapeutic impressions (\u03b2 = 13.12,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.001). Therapeutic impressions significantly influenced clinical advice (\u03c7\u00b2 = 54.03,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.001). Nonadherence was identified in 8% of cases.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>Pharmacology TDM service utilization for clozapine was steady and continuing in treatment-resistant schizophrenia patient care.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/indianjpsychiatry_375_26","type":"journal-article","created":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T08:00:50Z","timestamp":1789632050000},"page":"826-830","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Utility of clozapine trough level reporting in clinical practice: A four-year retrospective evaluation from India"],"prefix":"10.4103","volume":"68","author":[{"given":"Amol N","family":"Patil","sequence":"first","affiliation":[{"name":"Department of Pharmacology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pankaj","family":"Khatri","sequence":"additional","affiliation":[{"name":"Department of Clinical Hematology and Medical Oncology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sunil","family":"Sharma","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Smita","family":"Pattanaik","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Subho","family":"Chakrabarti","sequence":"additional","affiliation":[{"name":"Department of Psychiatry, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yogesh Dan","family":"Charan","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Namrata","family":"Singh","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alisha","family":"Kashyap","sequence":"additional","affiliation":[{"name":"Department of Experimental Medicine and Biotechnology, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandeep","family":"Grover","sequence":"additional","affiliation":[{"name":"Department of Psychiatry, PGIMER, Chandigarh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"R1-20261027","doi-asserted-by":"crossref","first-page":"103353","DOI":"10.1016\/j.ajp.2022.103353","article-title":"Clozapine research from India: A systematic review","volume":"79","author":"Grover","year":"2023","journal-title":"Asian J Psychiatry"},{"key":"R2-20261027","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1097\/JCP.0000000000001980","article-title":"The impact of therapeutic drug monitoring on clozapine dosing and clinical outcome in a tertiary care center in India: A retrospective study","volume":"45","author":"Jogi","year":"2025","journal-title":"J Clin Psychopharmacol"},{"key":"R3-20261027","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1055\/s-0043-116492","article-title":"Consensus guidelines for therapeutic drug monitoring in neuropsychopharmacology: Update 2017","volume":"51","author":"Hiemke","year":"2018","journal-title":"Pharmacopsychiatry"},{"key":"R4-20261027","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1097\/00004850-200505000-00007","article-title":"An inter-ethnic comparison study of clozapine dosage, clinical response and plasma levels","volume":"20","author":"Ng","year":"2005","journal-title":"Int Clin Psychopharmacol"},{"key":"R5-20261027","doi-asserted-by":"crossref","first-page":"4","DOI":"10.4103\/IJPSYM.IJPSYM_379_19","article-title":"Do Asian patients require only half of the clozapine dose prescribed for caucasians? A critical overview","volume":"42","author":"de Leon","year":"2020","journal-title":"Indian J Psychol Med"},{"key":"R6-20261027","first-page":"101918","volume":"48","author":"Naveen","year":"2020","journal-title":"ABCB1 and DRD3 polymorphism as a response predicting biomarker and tool for pharmacogenetically guided clozapine dosing in Asian Indian treatment resistant schizophrenia patients.\" Asian journal of psychiatry"},{"key":"R7-20261027","first-page":"CD009555","article-title":"Clozapine dose for schizophrenia","volume":"2017","author":"Subramanian","year":"2017","journal-title":"Cochrane Database Syst Rev"},{"key":"R8-20261027","doi-asserted-by":"crossref","first-page":"e00890","DOI":"10.1002\/prp2.890","article-title":"Inter\u2010ethnic differences in pharmacokinetics\u2014is there more that unites than divides?","volume":"9","author":"Olafuyi","year":"2021","journal-title":"Pharmacol Res 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